USB: MUSB: make non-OMAP platforms build with CONFIG_PM=y

Attempt to build MUSB driver with CONFIG_PM=y (e.g. in the OTG mode) on DaVinci
results in these link errors:

drivers/built-in.o: In function `musb_restore_context':
led-triggers.c:(.text+0x714d8): undefined reference to
`musb_platform_restore_context'
drivers/built-in.o: In function `musb_save_context':
led-triggers.c:(.text+0x71788): undefined reference to
`musb_platform_save_context'

This turned out to be caused by commit 9957dd9
(usb: musb: Fix compile error for omaps for musb_hdrc). Revert it, taking into
account the rename of CONFIG_ARCH_OMAP34XX into CONFIG_ARCH_OMAP3 (which that
commit fixed in a completely inappropriate way) and the recent addition of
OMAP4 support.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Acked-by: Felipe Balbi <felipe.balbi@nokia.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_core.h

@@ -470,7 +470,8 @@ struct musb_csr_regs {
 
 struct musb_context_registers {
 
-#ifdef CONFIG_PM
+#if defined(CONFIG_ARCH_OMAP2430) || defined(CONFIG_ARCH_OMAP3) || \
+    defined(CONFIG_ARCH_OMAP4)
 	u32 otg_sysconfig, otg_forcestandby;
 #endif
 	u8 power;
@@ -484,7 +485,8 @@ struct musb_context_registers {
 	struct musb_csr_regs index_regs[MUSB_C_NUM_EPS];
 };
 
-#ifdef CONFIG_PM
+#if defined(CONFIG_ARCH_OMAP2430) || defined(CONFIG_ARCH_OMAP3) || \
+    defined(CONFIG_ARCH_OMAP4)
 extern void musb_platform_save_context(struct musb *musb,
 		struct musb_context_registers *musb_context);
 extern void musb_platform_restore_context(struct musb *musb,